It is desirable that platen rolls which are light in weight and low in noise level during use should be used in printers etc. A lightweight platen roll core is known in which, for example, a shaft portion which is to be coupled to the drive shaft of a rubber platen is coupled, by means of ribs, to a cylinder portion on which a platen is to be fitted, such that cavities are defined between the shaft portion and the cylinder portion. The core of this type, however, resonates with sound waves produced during printing to cause air-column vibrations in the cavities and, therefore, produces undesirable noises. To reduce such noises, Japanese Utility Model Disclosure No. 60-166551, for example, discloses forming of ridges which protrude toward the cavities so that the sound waves produced by vibrations are irregularly reflected by the ridges and are canceled out.
However, the regulations on noise levels of printers, etc., tend to become more and more strict, further, and improvement of the sound-damping qualities is desirable.